Most motorized wheelchairs use a manual controller such as a joystick, chin controls or puff/sip scanners. In the case of a joystick controller, by way of example, a manually-engageable control lever is mounted on the arm of the wheelchair. The joystick is then pushed forwardly or rearwardly to respectively energize the drive wheels to carry out forward or rearward driving of the wheelchair. Lateral movement of the joystick, that is rightwardly or leftwardly, causes corresponding rightward or leftward steering of the wheelchair resulting from the corresponding adjustment in the motors driving the right and left wheels.
Traditionally, joystick controllers were of the inductive type which were well known and used for many years. That is, the lower end of the joystick mounted to a coil which was positioned between four stationary coils arranged in a generally rectangular pattern. The four stationary coils represented the forward, rearward, rightward and leftward directions. Movement of the joystick and its associated coil created, in the stationary coils to which the moving coil approached, appropriate voltage signals which were then transmitted to the wheelchair controller. This in turn appropriately drove the motors associated with the right and left drive wheels.
Wheelchair controllers have advanced. For example, U.S. Pat. No. 6,992,602 describes a joystick controller employing a non-contact principle for detecting joystick position. Specifically, the joystick controller using Hall-effect sensors or other magnetic proximity effect devices. The signals from the joystick are then sent to traditional control logic processors, as is known in the art.
A conventional wheelchair, such as the JAZZY™ 1120 made by Pride Mobility Products Corporation and described in U.S. Pat. No. 6,176,335, is shown in FIG. 1. This wheelchair is widely used and serves as an ideal context for the invention as described below. The wheelchair of the prior art includes electrically operable wheelchair 1 having seat 2, base 4 with a pair of motors (not shown) respectively coupled with the main support wheels 6, input device 8 (here a joystick), and a controller (not shown) coupled with input device 8 and the motors for controlling wheelchair operation in order to effect desired wheelchair movements. It can be seen from FIG. 1 that seat 2 is rigidly affixed to base 4.
Traditional and modern joystick controllers, while providing the greatest degree of control, do not provide hands-free control.